1. Field of the Invention
The present invention relates generally to testing equipment and, more specifically, to testing equipment for eddy current tube analysis. The present invention, a triple-action heat exchanger tube probe, is an electromagnetic probing device attached to a long flexible extension means which is, in turn, connected by electrical wiring running therethrough, to an analyzing device. The purpose of this type of device is to provide a means of probing and detecting defects within non-ferrous heat exchanger tubing material. This can be accomplished by providing an electromagnetic transmitting coil within the probe that can induce eddy currents through some distance within the tubing material in order to produce a corresponding magnetic field therein that will indirectly cause an induced output current to be produced within a receiving coil in the probe that may then be transmitted to analyzing equipment. Thereupon the input/output currents are compared with calibrated standards and algorithms used by specialized diagnostic software programs running on test equipment for a determination of the defect condition of the material under test. Because of limitations in computer technology test probes have been limited to using one the of electromagnetic coil pair per test.
Recent advances in computer technology, however, have lead to the development of test equipment with multiple input/output signal generating and processing capability allowing for the support of multiple-coil pair use in test probes. This breakthrough technology now yields more information per test than was possible with previous testing techniques. This is accomplished by focusing on the advantages of each coil pair and ignoring the disadvantages. The results of this technique yield great benefits. The preferred embodiment of the present invention, the Tri-Tip Probe, is a prime example of the new technology that provides a unique assembly of 3 distinct coil pair types.
The first coil pair in the assembly is known as the AC3 coil pair. They specialize in electronically erasing all gradual geometry changes and detect large defects within these areas. It is positioned first in the probe assembly in order to be effective in testing through the end of the tube.
The middle coil pair, known as the Differential coil pair, excel at detecting small defects and making accurate depth determinations on both the inside and outside of the tube but cannot be used to determine overall wear patterns.
The last coil pair in the Tri-Tip Probe assembly is known as the x-axis coil pair. X-axis coil configuration is excellent at detecting overall wear patterns on both sides of the tube because it faithfully follows the tube geometry. The composite radiation pattern results in a large lobe of energy that can be rotated to further troubleshoot located defects.
Each of these coil pairs adds data missed by the others and the composite effect removes all the disadvantages inherent in each pair separately. With its unique combination of coil pairs, The Tri-Tip Probe can provide more information from a single test then was previously possible from any other probe or series of individual tests.
2. Description of the Prior Art
There are other eddy current probing devices designed for eddy current tube analysis. Typical of these is U.S. Pat. No. 5,270,647 issued to Robert Beissner and Takashi Kikuta on Dec. 14, 1993.
Another patent was issued to Valentino S. Cecco et al. on Aug. 17, 1993 as U.S. Pat. No. 5,237,270. Yet another U.S. Pat. No. 4,855,677 was issued to William G. Clark et al. on Aug. 8, 1989 and still yet another was issued on Sep. 17, 1991 to Valentino S. Cecco et al. as U.S. Pat. No. 5,049,817.
Another patent was issued to William G. Clark on Nov. 26, 1991 as U.S. Pat. No. 5,068,608.